The size of a traditional vise is indicated by its clamp jaw width. The clamp holding depth corresponds to its clamp jaw width. The extent that a vise can clamp is in proportion to the size of a clamp jaw. If various shapes of work objects and requirement under processing work exceed the vise clamping capacity, the vise is unable to clamp and one size larger vise is needed.
If one is working on different sized objects alternately, he has to change vises all the time. It is not efficient and convenient.
This design provides two sets of variable vises that may extend in opposite directions by combining an additional sliding jaw, a fixed jaw and an original sliding jaw, a fixed jaw.
When a leading threaded shaft drives a sliding unit, it produces clamping depth variations on related two sets.
The knurls in a vertical, horizontal pattern or rectangular groove or multiple-stepped style pipe clamp claws on the additional clamp jaw may clamp and press a columnar work object in upright or horizontal position. It also may be applied to press a pattern by attaching a mold.